Basic set up for fretted instruments

Sometimes you end up with a cheap guitar that sounds pretty good but the intonation is rough on your ears and the action makes your fingers bleed. If it's not worth the cost of a set up, you might be able to make some adjustments yourself and make it a decent axe to keep around the house. I haven't done this on a guitar, but I've done work on my mandolin and ukulele, so if you average out the strings, it's the same basic principle. Before you get in over your head, do a little extra research, especially if you're inexperienced at adjusting the truss rod or handling small files or sharp blades.

1) Make sure the neck is straight. Put a capo on the first fret and push down the string on the last fret. There should be a tiny amount of space between the 8th fret and string. If there's nothing, loosen your truss rod. Too much, tighten it. Adjust it in quarter turns, and very slowly.

2) Adjust the bridge or saddle. In most cases, your bridge or saddle (the white piece on the bridge of an acoustic guitar), is going to be too high. There should be slightly more distance between the strings and frets as you move up the neck to allow for more vibration on the string, but too much will cause intonation problems. If it's an acoustic with one of those white plastic saddles, you can simply pop it out to file or sand the bottom side to lower it, or if it needs more height put something underneath it.

3) File out the slots on the nut. On almost every new instrument, especially cheap ones, the nut will need some work. Your strings should be very close to the first fret, otherwise you'll have intonation problems. The string vibration has a smaller amplitude here and is less likely the buzz. Professional guitar techs will have appropriate files for this job, but a set of these is almost as expensive as any instrument I'd have the nerve to work on so I use an exacto knife, nail file, and patience. Go very slowly and retest the string often. If you take out too much you'll need a new nut, or else figure out a way to carefully add a little glue in the slot.

4) Adjust the intonation. This can mean several things. Classical guitars, ukuleles, and many acoustics won't allow for much adjustment. But if your instrument has a movable bridge or individual adjustable saddles (as on most electrics), you can tweak the intonation. First put some fresh strings on and tune up. Then check the note at the 12th fret. It should be exactly in tune. If it's flat, move the saddle closer to the fretboard. If it's sharp, go the other way. Again, small movements do the trick.

If you have any problems, consult a professional before ruining your instrument. But if you have patience and enjoy doing this kind of work, I encourage you to try. I always smile when somebody picks up my $250 mandolin and comments on how nice it feels and I can tell them I set it up myself!